<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    article {
        width: 300px;
        height: 300px;
        border: 1px solid blue;
        display: grid;
        /* 指定最小和最大宽度 */
        grid-template-rows: repeat(3, 1fr);
        grid-template-columns: repeat(3, 1fr);
    }

    div {
        background-color: slateblue;
        background-clip: content-box;
        border: 1px solid green;
        padding: 10px;
        box-sizing: border-box;
    }
    /* 把第一个 div 放置到位置 */
    div:first-child{ 
        grid-row-start: 1;
        grid-column-start: 1;
        grid-row-end: 2;
        grid-column-end: 4;
    }
</style>

<body>
    <article>
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>4</div>
        <div>5</div>
        <div>6</div>
        <div>7</div>
        <div>8</div>
        <div>9</div>
    </article>

</body>

</html>